Aspirin exerts its effects through two primary mechanisms:

1. Antiplatelet Action:
   • Aspirin irreversibly inhibits cyclooxygenase-1 (COX-1) in platelets, preventing the synthesis of thromboxane A2 (TXA2), a potent promoter of platelet aggregation and vasoconstriction. This antiplatelet effect lasts for the lifespan of the platelet (7–10 days) (Lippincott, Lange).
2. Anti-inflammatory, Analgesic, and Antipyretic Actions:
   • Aspirin inhibits cyclooxygenase-2 (COX-2), reducing the production of prostaglandins and thromboxanes. This results in decreased inflammation, pain, and fever (BNF).

1. Cardiovascular Disease Prevention:
   • Primary Prevention: Controversial; used selectively in high-risk individuals.
   • Secondary Prevention: Reduces the risk of myocardial infarction (MI), stroke, and cardiovascular death in patients with a history of ACS, stroke, or peripheral arterial disease (PAD) (BNF).
2. Pain Relief (Analgesia):
   • Effective for mild to moderate pain, including headaches, dental pain, and musculoskeletal pain (Lippincott).
3. Fever Reduction (Antipyresis):
   • Used to manage fever in adults and children (though caution is advised in children due to the risk of Reye’s syndrome) (Lange).
4. Anti-inflammatory:
   • Used in conditions like rheumatoid arthritis and rheumatic fever (BNF).

• Cardiovascular Prevention:
  • 75–325 mg once daily (lower doses preferred for long-term use to minimize side effects) (BNF).
• Pain and Fever:
  • 325–650 mg every 4–6 hours as needed (max 4 g/day) (Lippincott).
• Rheumatic Fever/Arthritis:
  • 4–8 g/day in divided doses (Lange).

Administration:

• Can be taken with or without food, but taking it with food may reduce gastrointestinal irritation.
• Enteric-coated or buffered formulations are available to minimize gastric side effects (BNF).

• Common: Gastrointestinal irritation, dyspepsia, and nausea (Lippincott).
• Serious: Gastrointestinal bleeding, peptic ulcers, hemorrhagic stroke, and Reye’s syndrome (in children with viral infections) (BNF).
• Allergic Reactions: Bronchospasm, urticaria, and anaphylaxis (especially in patients with asthma or nasal polyps) (Lange).

• Peptic Ulcer Disease: Contraindicated in active ulcers or a history of gastrointestinal bleeding (BNF).
• Children and Adolescents: Avoid in those under 16 years (unless specifically indicated, e.g., Kawasaki disease) due to the risk of Reye’s syndrome (Lippincott).
• Pregnancy: Avoid in the third trimester due to the risk of premature closure of the ductus arteriosus (Lange).
• Bleeding Disorders: Use with caution in patients with hemophilia or other bleeding disorders (BNF).

• Anticoagulants (e.g., warfarin): Increased risk of bleeding (Lippincott).
• Other NSAIDs (e.g., ibuprofen): May reduce aspirin’s antiplatelet effects and increase gastrointestinal toxicity (Lange).
• Corticosteroids: Increased risk of gastrointestinal ulcers and bleeding (BNF).
• Methotrexate: Aspirin can increase methotrexate toxicity by reducing its renal clearance (Lippincott).

Aspirin is the generic name for this medication. It is marketed under various brand names, including Bayer Aspirin®, Ecotrin®, and Disprin®. Generic versions are widely available and cost-effective.